[Qemu-devel] [PATCH 1/3] block: Add '-blockdev' command line option

[Kevin Wolf <kwolf@redhat.com>]

This is an option that is directly mapped to the blockdev-add QMP
command. It works more or less like -drive, except that it doesn't
create a BlockBackend and doesn't support legacy options.

This patch adds minimal documentation, the next patches will improve it.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 blockdev.c              | 12 +++++++++++
 include/sysemu/sysemu.h |  1 +
 qemu-options.hx         | 12 +++++++++++
 vl.c                    | 57 +++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 82 insertions(+)

diff --git a/blockdev.c b/blockdev.c
index 76b86ab..5931383 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -4075,3 +4075,15 @@ QemuOptsList qemu_drive_opts = {
         { /* end of list */ }
     },
 };
+
+QemuOptsList qemu_blockdev_opts = {
+    .name = "blockdev",
+    .head = QTAILQ_HEAD_INITIALIZER(qemu_blockdev_opts.head),
+    .desc = {
+        /*
+         * no elements => accept any params
+         * validation will happen later
+         */
+        { /* end of list */ }
+    },
+};
diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
index ee7c760..1a2013a 100644
--- a/include/sysemu/sysemu.h
+++ b/include/sysemu/sysemu.h
@@ -238,6 +238,7 @@ bool defaults_enabled(void);
 extern QemuOptsList qemu_legacy_drive_opts;
 extern QemuOptsList qemu_common_drive_opts;
 extern QemuOptsList qemu_drive_opts;
+extern QemuOptsList qemu_blockdev_opts;
 extern QemuOptsList qemu_chardev_opts;
 extern QemuOptsList qemu_device_opts;
 extern QemuOptsList qemu_netdev_opts;
diff --git a/qemu-options.hx b/qemu-options.hx
index 0b621bb..542c483 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -513,6 +513,18 @@ Use @var{file} as CD-ROM image (you cannot use @option{-hdc} and
 using @file{/dev/cdrom} as filename (@pxref{host_drives}).
 ETEXI
 
+DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev,
+    "-blockdev driver=driver[,node-name=n][,read-only=on|off]\n"
+    "       [,cache.direct=on|off][,cache.no-flush=on|off]\n"
+    "       [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n"
+    "       [,...driver specific...]\n", QEMU_ARCH_ALL)
+STEXI
+@item -blockdev @var{option}[,@var{option}[,@var{option}[,...]]]
+@findex -blockdev
+
+Define a new block driver node.
+ETEXI
+
 DEF("drive", HAS_ARG, QEMU_OPTION_drive,
     "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n"
     "       [,cyls=c,heads=h,secs=s[,trans=t]][,snapshot=on|off]\n"
diff --git a/vl.c b/vl.c
index fca0487..dbf7849 100644
--- a/vl.c
+++ b/vl.c
@@ -122,6 +122,9 @@ int main(int argc, char **argv)
 #include "sysemu/replay.h"
 #include "qapi/qmp/qerror.h"
 #include "sysemu/iothread.h"
+#include "qapi-visit.h"
+#include "qapi/qobject-input-visitor.h"
+#include "qapi/dealloc-visitor.h"
 
 #define MAX_VIRTIO_CONSOLES 1
 #define MAX_SCLP_CONSOLES 1
@@ -1132,6 +1135,46 @@ static int cleanup_add_fd(void *opaque, QemuOpts *opts, Error **errp)
 #define MTD_OPTS ""
 #define SD_OPTS ""
 
+static int blockdev_init_func(void *opaque, QemuOpts *opts, Error **errp)
+{
+    BlockdevOptions *options;
+    Visitor *v = NULL;
+    Error *local_err = NULL;
+
+    QDict *opts_dict = qemu_opts_to_qdict(opts, NULL);
+    QObject *crumpled = qdict_crumple(opts_dict, true, &local_err);
+    if (local_err) {
+        goto fail;
+    }
+
+    v = qobject_string_input_visitor_new(crumpled);
+    visit_type_BlockdevOptions(v, NULL, &options, &local_err);
+    if (local_err) {
+        goto fail;
+    }
+    visit_complete(v, opts);
+
+    qmp_blockdev_add(options, &local_err);
+    if (local_err) {
+        goto fail;
+    }
+
+fail:
+    QDECREF(opts_dict);
+    qobject_decref(crumpled);
+
+    visit_free(v);
+
+    v = qapi_dealloc_visitor_new();
+    visit_type_BlockdevOptions(v, NULL, &options, NULL);
+    visit_free(v);
+
+    if (local_err) {
+        error_propagate(errp, local_err);
+    }
+    return !!local_err;
+}
+
 static int drive_init_func(void *opaque, QemuOpts *opts, Error **errp)
 {
     BlockInterfaceType *block_default_type = opaque;
@@ -2990,6 +3033,7 @@ int main(int argc, char **argv, char **envp)
     module_call_init(MODULE_INIT_QAPI);
 
     qemu_add_opts(&qemu_drive_opts);
+    qemu_add_opts(&qemu_blockdev_opts);
     qemu_add_drive_opts(&qemu_legacy_drive_opts);
     qemu_add_drive_opts(&qemu_common_drive_opts);
     qemu_add_drive_opts(&qemu_drive_opts);
@@ -3122,6 +3166,13 @@ int main(int argc, char **argv, char **envp)
                     exit(1);
                 }
                 break;
+            case QEMU_OPTION_blockdev:
+                opts = qemu_opts_parse_noisily(qemu_find_opts("blockdev"),
+                                               optarg, false);
+                if (opts == NULL) {
+                    exit(1);
+                }
+                break;
             case QEMU_OPTION_set:
                 if (qemu_set_option(optarg) != 0)
                     exit(1);
@@ -4409,6 +4460,12 @@ int main(int argc, char **argv, char **envp)
     }
 
     /* open the virtual block devices */
+    if (qemu_opts_foreach(qemu_find_opts("blockdev"), blockdev_init_func,
+                          NULL, &err)) {
+        error_report_err(err);
+        exit(1);
+    }
+
     if (snapshot || replay_mode != REPLAY_MODE_NONE) {
         qemu_opts_foreach(qemu_find_opts("drive"), drive_enable_snapshot,
                           NULL, NULL);
-- 
1.8.3.1